US Navy orders probe into Pacific fleet after 10 sailors go missing in second major collision in months

The US Navy has ordered a broad investigation into the performance and readiness of the Pacific-based 7th Fleet after a collision between the USS John S. McCain and an oil tanker.

The move came as vessels from several nations searched Southeast Asian waters for 10 US sailors missing since the incident on Monday morning.

It was the second major collision in the last two months involving the Navy's 7th Fleet.

Seven sailors died in June when the USS Fitzgerald and a container ship collided in waters off Japan.

Navy Admiral John Richardson, the chief of naval operations, will call for a pause in operations and seek a deeper look at how the Navy trains and certifies its forces that are operating around Japan, Defence Secretary Jim Mattis said.

"He has put together a broader inquiry to look into these incidents," he said, referring to the two recent collisions and other accidents at sea.

Mr Mattis spoke to reporters in Amman, Jordan, where he is travelling.

Vessels and aircraft from the US, Indonesia, Singapore and Malaysia are searching for the missing sailors.

Four other sailors were evacuated by a Singaporean navy helicopter to a hospital in the city-state for treatment of non-life threatening injuries, the Navy said.

A fifth was taken to the hospital by ambulance after the destroyer arrived in Singapore under its own power, the Maritime and Port Authority of Singapore said.

The McCain had been heading to Singapore on a routine port visit after conducting a sensitive freedom-of-navigation operation last week by sailing near one of China's man-made islands in the South China Sea.

The collision east of Singapore between the guided missile destroyer and the 183-metre (600-foot) Alnic MC ripped a gaping hole in the destroyer's hull.

The Navy's 7th Fleet said "significant damage" to the McCain's hull resulted in the flooding of adjacent compartments including crew berths, machinery and communications rooms.

A damage control response prevented further flooding, it said.

The destroyer was damaged on its port side aft, or left rear, in the collision about 4.5 nautical miles (8.3 kilometres) from Malaysia's coast but was able to sail on to Singapore's naval base.

Malaysia's Maritime Enforcement Agency said the area is at the start of a designated sea lane for ships sailing into the Singapore Strait, one of the world's busiest shipping lanes.

A photo tweeted by Malaysian navy chief Ahmad Kamarulzaman Ahmad Badaruddin showed a large rupture in the McCain's side near the waterline.

Another US naval vessel, the amphibious assault ship USS America, arrived in Singapore and was helping with damage control efforts on the McCain and with the search for the missing sailors, the Navy's 7th Fleet said.

It will also feed and house sailors from the stricken ship.

One of the injured sailors, Operations Specialist 2nd Class Navin Ramdhun, posted a Facebook message telling family and friends he was ok and awaiting surgery for an arm injury.

He told The Associated Press in a message that he could not say what happened: "I was actually sleeping at that time. Not entirely sure."

The Singapore government said no crew were injured on the Liberian-flagged Alnic, which sustained damage to a compartment at the front of the ship some seven metres (23 feet) above its waterline.

There were no reports of a chemical or oil spill.

Several safety violations were recorded for the tanker at its last port inspection in July.

The Navy review will look at the fleet's performance including personnel, navigation capabilities, maintenance, equipment, surface warfare training, munitions, certifications and how sailors move through their careers.

"The chief of naval operations' broader inquiry will look at all related accidents, incidents at sea" involving ships of the 7th Fleet, Mr Mattis said.